1. Field of the Invention
This invention relates to shutters for use on exterior wall openings such as doors and windows, and more particularly to shutters capable of withstanding high impacts from flying debris, including large debris, and particularly suited for use in violent storms such as hurricanes.
2. Description of Related Art
Shutters for the protection of exterior doors and windows during storms are known in the art. For example, in coastal areas, shutters, commonly called hurricane shutters, are regularly used to protect doors and windows during the high winds generated by hurricanes and other storms. Shutters are also used by residents during periods of extended absence.
Shutters are typically placed on the exterior of a door or window and are operated either from the outside or inside of the building structure. Operation from the interior of a building structure is particularly important for use in two or more story homes or high-rise apartment buildings, hotels, and the like where exterior operation might be cumbersome.
Shutters may be made of one or more pieces of metal or other sturdy material placed in a supportive frame external to the window or door to be protected. Shutters may be configured in panels which have a perimeter framework holding an interconnected plurality of vertical or horizontal pieces of material called slats, which are commonly generally rectangular in shape and made of metal. The slats may or may not provide small openings or slits to allow for ventilation and entry of light.
Shutter panels may be used singularly in an external supportive frame, but typically are used in pairs and multiple pairs to cover wider areas without having to make extremely large shutter panels. A panel, or pairs and multiple pairs of shutter panels, may be held in an external supportive framework having a guide track, or parallel guide tracks, such that the panel, or the plurality of panels, can slide horizontally with each panel on a separate track.
The supportive framework can be made wider than the door or window to be protected permitting the panel or panels to be stored in the open position, on one side or both sides of, and completely unobstructing, the door or window opening. Typically, multiple panels are stored on either side of the window or door, and the width of the panels and frame are selected such that the panels mate together in a closed position completely covering the door or window, and stack in parallel orientation in the open position completely unobstructing the door or window.
An example of a shutter assembly, similar to that described herein, and which is completely operable from the interior of the building structure, is shown in U.S. Pat. No. 3,452,477, to Sassano (the '477 patent), the disclosure of which is incorporated herein by reference.
In many coastal hurricane prone areas of the country, storm shutters must meet building code requirements. In the aftermath of hurricane Andrew, which hit South Florida on Aug. 24, 1992, the building code requirements in South Florida were made significantly more stringent. The South Florida Building Code, one of the most stringent in the United States, now requires storm shutters to meet large and small missile impact tests For example, for a large missile impact test, the shutter must withstand two impacts from a 2.times.4 inch wooden missile, weighing 9 pounds, fired from an air cannon at 50 feet per second (34 m.p.h.).
The shutters currently available, such as those disclosed in '477, cannot withstand the described large missile impact test. Among the shutter's failures in the test, the slats collapse, separating at the interconnection points and from the perimeter frame allowing the missile to pass through the shutter. To meet the stringent building code requirements, shutter manufacturers are adding backing support material to strengthen existing shutter designs. This often requires modification or replacement of existing support frame members. In addition, for panels having slats with slits for ventilation and/or lighting as shown in FIG. of '477, the backing support material can block the slits preventing ventilation and sunlight.
There exists a need for a storm shutter, similar to that described in the '477 patent, that during operation can be stacked in the storage configuration, and which can be vented or unvented. The shutter can be similar in appearance to existing shutters, such as the shutters of the '477 patent, thus allowing it to be retrofited to existing products already installed. The shutter must withstand stringent high impact large and small missile tests as mandated in some communities such as South Florida, as well as hurricane force winds.